1. Field of the Invention
The present invention relates to a multi-tube heat exchanger and an air conditioner having the same, and more particularly to a small-sized multi-tube heat exchanger and an air conditioner having the same suitable for vehicles.
2. Description of the Related Art
A conventional air conditioner is depicted in FIG. 12. In FIG. 12, a path 100 for air subjected to heat exchange is formed in an air conditioner 200. The opening degrees of vehicle compartment inside air intake port 112 and vehicle compartment outside air intake port 113 are adjusted by rotary-type damper 101. Controlled inside air (REC.) and/or outside air (FRE.) are thereby introduced into air path 100 as air subjected to heat exchange.
In air path 100, a blower 102, a heat exchanger 103 and heater 104 are provided, in this order, from the upstream side to the downstream side in the passage direction of air subjected to heat exchange (i.e., the direction shown by arrow AF in FIG. 12). Damper 105 is provided between heat exchanger 103 and heater 104. The flow of the air subjected to heat exchange into heater 104 and the degree of air mixing are controlled by adjustment of damper 105. Air path 100 is diverged into discharge ports 106, 107 and 108 at positions downstream of heater 104. Dampers 109, 110 and 111 are provided between air path 100 and discharge ports 106, 107 and 108, respectively.
In such an air conditioner 200, air introduced into air path 100 through intake port 112 and/or intake port 113 passes through heat exchanger 103, and as needed, passes through heater 104, and thereafter, the air is discharged into the interior of the compartment of the vehicle through one or more discharge ports communicated with air path 100 opened selectively by operation of dampers 109, 110 and 111.
More concretely, in a cooling mode, heat exchanger 103 is operated, air flow into heater 104 is intercepted by closing damper 105, and operation of heater 104 is stopped. In a heating mode, operation of heat exchanger 103 is stopped, damper 105 is fully opened, and heater 104 is operated under a condition where the main stream of air having passed through heat exchanger 103 is directed to heater 104. In an air mixing mode, heat exchanger 103 is operated, damper 105 is semi-opened as shown in FIG. 12, and heater is operated under a condition where a part of the main stream of air passing through air path 100 is directed to heater 104. Air having passed through only heat exchanger 103 and air further having passed through heater 104 after passing through heat exchanger 103 are mixed at a position downstream of heater 104 to control the temperature of the mixed air. The controlled air is discharged through one or more discharge ports.
In the above-described air conditioner 200, a specified directivity is given to a part of, or the whole of the main stream of air subjected to heat exchange by adjustment of the opening degree of damper 105 provided in air path 100, thereby selecting a desired air conditioning mode.
However, in such a controlling mechanism where damper 105 is provided between heat exchanger 103 and heater 104, and the directivity of the main stream of air is controlled by damper 105, a space for controlling the direction of the main stream of air (in FIG. 12, a space between heat exchanger 103 and heater 104) and a space for rotational operation of damper 105 must be provided. Because of these space requirements, air path 100 is enlarged or lengthened, and ultimately, the air conditioner itself must be made large. Recently, air conditioners for vehicles are required to be made smaller, because of, for example, the development of vehicles mounted with an air bag system or/and a navigator system. A conventional air conditioner such as the above-described one cannot satisfy such a size requirement because if the air conditioner is merely formed smaller, the heat exchange property of the air conditioner is necessarily reduced.